This talk is part of the Fountain Fundamentals Conference, July 10-11, 2013, Kansas City, MO.
A Manageable Approach for the Maintenance of Fountain Water
Striegel: Our next speaker today is Robert Krueger. He’ll be talking about a manageable approach for the maintenance of fountain water. Robert Krueger is an Objects Conservator and proprietor of Cascadia Art Conservation Center in Portland, Oregon. He has a Master’s Degree in Conservation from the State University of New York at Buffalo and is a professional associate of the American Institute for Conservation of Historic and Artistic Works. Robert works with municipal collectors, universities, museums, and private collectors. His approach to conservation includes traditional conservation treatments as well as the preservation of artworks through a preventative approach. Robert works regularly with the commissioning agencies and artists in reviewing materials and methods to guarantee the best approaches for longevity and durability. Robert’s interest in defining a manageable care methodology for fountains was forged after studying the effects of chlorinated fountain water on stainless steel sculpture in downtown Portland in 2007. Robert….
Krueger: Thank you. Good Morning. Can everybody hear me okay? The objective of my talk today is to convince you that maintaining water in a fountain is easy and I will not take too much of your time. The reason I start with this statement is because I have found that people give up even before they get started because the maintenance of water chemistry sounds just way too complicated. Water is the most important feature to maintain when it comes to the preservation of a fountain. I’ll go through general processes of maintain a fountain. I’ll go through starting with the cleaning of the fountain then testing and making adjustments to the water chemistry. Finally I’ll go into algae prevention and changes that can be made to improve the mechanical system and ease maintenance.
If you are starting with a fountain that has algae or other unwanted biological growth, then start by draining the fountain’s water. Clean all the surfaces that contact the water and also those near the water. Using an appropriate brush and I prefer Triton X-100 but other surfactants work too and water, cleaning the surface until visible algae is removed. If you want to be extra cautious you may use something like D-2 to be sure that the algae are dead. Rinse until you removed all the surfactant, if there is scale in the fountain or insoluble mineral salts; this would be a great time to remove those too. Now refill the fountain with water. Most often a fountain will be filled with municipal or tap water which is both minerals and organics from plants and also from human sources such as fertilizers and other chemicals. This will vary greatly depending on where in the country you are. I know here in Kansas City, the water is full of great things, you know full of fertilizer bits and the water is very hard so you have lots of minerals as opposed to where I’m based in Portland, Oregon where we have very soft water. It’s very clean and much different. But no matter where the water comes from it will have to be tested and water chemistry will need to be adjusted.
If you begin to gloss over as I continue this talk, don’t lose hope. After the explanation of why, I’ll get into a step-by-step method for taking readings and making adjustments. It’s not necessary to have a deep understanding of the water chemistry in order to maintain the water but if you’re like me, having some understanding will help you remember what you are doing and extra knowledge never hurts. I understand Martin Burke will be leading a field section tomorrow on water quality testing. This will be a good opportunity to see how it’s really done.
The mineral content of water is important. Minerals held in suspension are measured in hardness, a term derived from the effects of particular water on soap. Hardness can be compared to levels of saturation which is a state where a solution contains the maximum amount of possible dissolved solute in a stable situation under prevailing conditions of temperature and pressure. Soft water can be compared to unsaturated water. When the water is unsaturated, it is stable and able to hold more dissolved solids. Unsaturated water will leach minerals from stone, metals, masonry, and any available source including artworks. The opposite extreme is very hard or supersaturated water. In a supersaturated state the water cannot hold the amount of minerals, the dissolved solids in suspension and they will precipitate out of solution forming deposits referred to as scale. In fountains, mineral saturation is the goal.
Hardness is affected by several factors such as pH, temperature, and of course the amount of minerals in the water. All of these factors affect each other and the changes in one will affect all the other factors. For example, in most cases a rise in temperature increases the solubility of minerals, meaning that if water starts off as balanced but then the water temperature increases, the warmer water will now have the ability to hold more mineral. However, the solubility of calcium carbonate decreases as water temperature increases. Fortunately you don’t have to figure all this out on your own. To be sure that water in a fountain is stable and at the point of saturation, the water is tested to measure pH, calcium hardness, temperature and the ability to hold a pH. The result from this testing is then plugged into a calculation to find weather the water is bound. The result from the calculation will yield a number referred to as a saturation index. This slide shows the, I think you call it a slide rule but basically the device you use, you line up the numbers from your testing and it gives you the saturation index number.
My preferred method for finding the saturation index is to use a Taylor brand K-2006 test kit. I recommend Taylor brand kits because of their reliability, ease of use and the ability to accurately measure the water constituents within desirable ranges. There are other methods for testing and as long as the recommended factors can be reliably tested, then other procedures may be used. The K-2006 is available from your local pool suppliers, spa store or you can order it online. The kit comes with all the reagents needed to make colorimetric measurements. Each individual factor is tested then using the results of each test and the slide rule calculator I just showed, the saturation index can. The approach for a simple fountain is to test the water weekly and make adjustments as needed. Weekly testing and adjustments should only take about ten to twenty minutes once you’ve kind of established the routine, also depending on whether or not you need to make adjustments at that time. I will discuss how to make changes in order to balance the water later in this talk.
No matter what type of fountain you have, balanced water is the starting point for a fountain with clean, clear water that is aesthetically pleasing and least likely to harm the artwork or the fountain itself. From this point, maintaining a fountain depends on how the mechanical system is setup. If the fountain is simply a small reservoir of water, a pump and a rubber hose, then there are only a few things you can do. If you have more complex mechanical systems then there are more options for treating the water to keep it clean, balanced and algae free. As water evaporates, more water can be added to a fountain until the water becomes too hard. Because of the limited capacities of the mechanical system in a simple fountain and lack of any filtration system, it is likely the fountain will need to be periodically drained and refilled. In a simple fountain, there are few options for algae prevention. One option of course is to drain the fountain whenever algae appear. The other option is to use an algaecide. In many cases it is practical to use halogens such as chloride or bromide or metals like copper or silver to control unwanted growth. Chlorine is the most common method used to eliminate unwanted biological growth. Chlorine used in a fountain can be effective at disinfecting water but may have other unwanted side effects. Chlorine used in an outdoor feature will add swimming pool odor to the surrounding areas. Chlorine and other halogens can deteriorate the mechanical systems of the artwork in contact with the chlorinated water or the vapors from these waters.
Copper and silver are commonly used to control biological growth in water. Some studies have shown that particular growths in accommodation of copper and silver work better. Copper acts as an algaestat rather than an algaecide retarding and preventing growth but not actually killing established algae. Silver is an algaecide for pink algae but otherwise is a better bactericide. The use of metallic algaecides will eventually cause staining on surfaces such as basins and artwork.
Another option for killing algae is to use a quaternary ammonium also referred to as a quat. Quats are effective at killing algae by disrupting the cell wall. The downside of using a quat is that they have a limited effect on a variety of biological growth and even more important they can cause foaming in the water which isn’t particularly wanted in most fountains. An alternative to a quat is something called a polyquat. Poly-quats kill algae by adhering electrostatically to the outer cell membrane blocking them from nutrients. Poly-quats will also act as a flocking agent for other organic matter. Poly-quats are sold for use in swimming pools, spas, and ponds. The directions on the bottle tell how much to add to the water each week. I prefer rather than adding weekly doses of poly-quats a more precise method. If there is a lot of organic matter in the water, the poly-quats can be used up more quickly. If the water is relatively clean then the poly-quats will continue to be available for algaecide effect. Using a Taylor K-1582 test kit, I can rely on parts per million of quantities available poly-quat readings.
With more advanced mechanical systems there is a greater ability to control the water and restrict the water’s ability to support life. Adding a filter to the system will increase the ability to maintain balance and algae free water. There are many levels of filtration such as screens, activated charcoal, particulate filtration, depleted media, sand filters, and diatomaceous earth filters. Along with filtration, some systems have UVC sanitizers. UVC destroys bacteria, viruses, and fungi. The killing of organisms is expressed as a product of UVC energy and time. The effectiveness can be obtained with high intensity UVC energy in a short amount of time or a longer exposure to a low intensity of UVC radiation. A UVC radiation penetrates the organism causing a disruption in unsaturated bonds which leads to biological change or kills them. UVC is easily blocked and can only penetrate a certain amount of water before it is effective. In order for UVC systems to work optimally, the water must be filtered before being exposed. Another level of control is to limit the nutrients within the water. Nitrogen, phosphorus, sulfur, carbon and iron and many trace minerals are required for algae to grow. When waters are enriched with an abundance of these elements the water is considered eutrophic. In a eutrophic state the water is highly productive for biological growth. In terms of water quality, eutrophic waters are considered poor. Mesotrophic water has these nutrients but in limited quantities allowing some plant growth. In a Mesotrophic state, the water is considered good quality. For most fountains the goal is to have a very non-productive water or oligotrophic water. Oligotrophic water is considered to be of the best excellent quality and would be very well suited for cleaning algae free water in your fountain.
The nutrients required in large quantities for algae to grow are carbon, nitrogen, phosphorus, sulfur and iron. These nutrients are absorbed by plants and fix stoichiometric ratio. Any one of these will limit the algae’s ability to grow. Phosphate is used in the formation of cell walls and is crucial to the backbone structure of DNA. Limiting phosphates from the water will therefore limit organic growth. From what I have found, unless your fountain is supplied from a distiller or has a diatomaceous filter then the practical control of phosphate is very difficult.
Now I’ll cover some ways in which to make adjustments to the fountain which will apply to all fountains. The maintenance may sound time consuming however once the system is regularly maintained and these procedures become ritual, maintenance will be a relatively quick process. Using a checklist, keep a written record of every time maintenance is performed. This will be helpful in the long term to establish patterns of change. Start by checking the condition of the water weekly. After a couple of months of testing and making adjustments, you might find twice or even once per month is enough. The larger the body of water and especially if it is indoors, the more resistant to change it will be. Outdoor fountains will likely need more attention and the amount of attention needed may also be seasonally adjusted. Begin with a visual and tactile inspection; record your observations as well as the results from the water chemistry tests. In time, you’ll start to see relationships between the test data and your observations. Inspect for any algae both visually and by feeling the surface. If surfaces feel slimy then organic growth is beginning. If applicable, wash away dust and accumulated debris settled around the fountain and may fall into the water. Also use a net to remove any debris from the water. Inspect the mechanical system from anything out of the ordinary, a quick overall visual inspection of the exposed plumbing and mechanical system. Test the water and make adjustments as needed.
If part of your approach is to limit phosphate then test for phosphate using the Taylor Kit K-1106. Algae thrives at phosphate levels above 125 parts per million of orthophosphate. Before overall water chemistry is adjusted, the phosphate levels need to be corrected if possible. The easiest way to do this is to lower the phosphate levels by draining some of the water from the fountain and refilling it with phosphate free water. If you are filling your fountain with municipally supplied water you may want to test the tap water first because if it contains more than 125 parts per million, then this won’t work. If you are refilling with distilled water, then this method will work. Removing phosphate from water is possible using chelating agents but from what I have found this is usually not practical in a fountain because once the phosphate is chelated, it must be removed or it will be released back into the water. If your using standard diatomaceous filters then you can backwash those filters otherwise it may not be reasonable to attempt lowering the phosphate levels. After making adjustments to the water for phosphate levels, check the phosphate levels again in 24 hours.
Once phosphate levels are acceptable proceed with the rest of the water chemistry testing. For all fountains, using the Taylor K-2006 test kit and a thermometer, test conditions of the water and find the saturation index number. When the water chemistry test results indicate changes are needed, the additive should be placed directly into the holding tank or the area where most waters are stored within the fountain. If additives are dry chemicals, they should be diluted in water before they are added to the fountain. This will allow for better dispersal. It is preferable to add too little rather than too much. It is easier to add a little bit more rather than remove too much that’s been added. Be sure to measure the amount of water in the holding tank before calculating additions. If adjustments are needed based on the saturation index results, begin with the total aqualinity will affect the pH. It may sound counter intuitive but total aqualinity is not adjustment for pH but rather even though it affects the overall pH, it functions as a buffer to resist fluctuations in the pH. If the total aqualinity is low, add sodium bicarbonate or baking soda or a product called Aqualinity F. After 24 hours check the levels again. If it’s still too low, add more. If the total aqualinity is high, drain some of the water from the fountain and add fresh water to the fountain. After 24 hours check for total aqualinity again.
After total aqualinity, pH is the next crucial adjustment. If the pH is too low add soda ash, sodium bicarbonate or a product called pH UP. After 24 hours, check the level again. If the pH is too low add more calcium carbonate. If the pH is too high drain the water from the fountain and add fresh water to the fountain, test after 24 hours. After adjustment have been made to the pH, then recheck the total aqualinity.
Finally, test the waters for hardness and its total calcium carbonate. If the hardness is too low then add liquid calcium carbonate or calcium chloride. One should always question if chloride is being added around a sculpture and in this case, the amount of free chlorine being introduced into the system should not pose any harm to the artwork. Never add calcium hypochlorite. This is a product for adding chlorine to pools and will be harmful to the system and to the artwork. If the hardness is too high drain some of the water from the fountain and add fresh water to the fountain and after 24 hours check for hardness again. It may be worthwhile to also test the water supply for hardness. If adjustments were made to lower the hardness retest the total aqualinity and pH. And even though I make this sound like very tedious long procedures, it really once you get it down it’s a very quick process to check all these things and it becomes very routine.
Next check the polyquat levels using a Taylor K-1582 test kit, one can rely on parts per million quantities available polyquat readings. All my research is based on reading other people’s research and a lot of this information comes from municipal water suppliers and the procedures that have been used over the years and over the centuries for taking care of city water and also from health department ratings and so these numbers for polyquats I came up with, I’ve yet to be able to test. Talking to Martin Burke earlier, he was using I believe three parts per million of polyquats. I would suggest using twenty parts per million to start and ten letting that drop down to ten. So there’s some room for testing and adjusting down to get the minimal amount of polyquats needed to keep algae from growing. And my ten parts per million is based on health department recommendations for things like hand sanitizers, so my concern is trying to match the needs of people who feel fountains should be treated as swimming pools, we want to protect human health and so that’s why I put in ten parts per million because I’m trying to cover everything that would be covered by the chlorine.
If your fountain has a media filter then add inspecting the media filter to the weekly maintenance. I recommend installing pressure gauges on both sides of that filter. This affords a quick and easy way to judge if filters are clogged and need replacing. Other types of filters are more complicated. If you have a filter that you are not familiar with read the manual or refer to a consultant. If there is a UVC sanitizer installed the read the owner’s manual, find out how often the lamp should be replaced and how to maintain the unit. Many of the higher end units have built in cleaning mechanisms that will clean the quartz casing around the lamp so accumulated grime will not block the effects of the UVC radiation. Some units also have ports built in that allow the attachment of the UVC monitor. If the UVC sanitizer has a window, be aware that this window only tells you that the unit is on but not an indication of the amount of UVC that is being produced. Usually after about ten to twelve months of continuous use the UVC output has dropped to a level where it is no longer effective and needs to be replaced. When you are using UVC sanitizer, it is important to review the manual that came with the sanitizer to make sure the water is maintained in a way that maximizes the sanitizer’s ability to radiate the water. Here are some examples of parameters I use based on the needs of the UVC sanitizer for the Noguchi fountain here at the Nelson Adkins Museum of Art.
Turbidity, manganese, total suspended solids and iron are measured using a colorimeter. For those test you may rely on your local pool supply store. Many of these suppliers have colorimeters in their stores so they can provide their clients with the test results and usually their charge is nothing to minimal. Another sanitation device you may find is the ozone generator. These add ozones go into the water directly. These systems also need maintenance which should be outlined in the manual that came with them. While I have seen that these work really well the possibility of adding ozone to the surrounding environment should be considered. Ozone can cause problems for people with asthma and cause degradation of artworks in the area.
That is the end of my trying to convince you that it is really easy to maintain a fountain.
Striegel: Do we have questions. Yes, David.
David: Are you seeing, we’ve been specifying companies come in and use large reverse osmosis systems usually like a trailer that they can park for 24 hours to reduce the calcium hardness and really anything in the water. Are you seeing that more and more for larger fountains where throwing away water really is a bad option?
Krueger: You know that’s a really good question. I haven’t worked with reverse osmosis. I can see how it would be beneficial but I’m kind of focusing on trying to make this sound very manageable. Yes, so a very large fountain yes, you would definitely have to consider the cost of throwing out the water but have you found that it works really well or do you know?
David: These systems they can come in and in 24 hours they can drop the hardness to zero. They really clean up the water so if that’s done every year or two for big fountains then you don’t need to throw away water. Especially incoming water might be so high to begin with.
David: You may not be fixing anything by just throwing it away and starting over.
Krueger: Well it definitely gives me something else to look into; yeah that’s a great …
David: And another thing that I’m seeing and I was wondering if you had any experience with is using magnets for decalcifiers which really just keep the hardness in suspension, it doesn’t remove it like an RO system but helps keep it in suspension so it doesn’t play out and show up on the surfaces.
Krueger: I’m not familiar with those. I’d have to look into that because I’m not sure how that would work well. Because everything that I look at as far as taking care of the water chemistry is rather than try to keep things in suspension, trying to keep oversaturated water not oversaturated, you know to remove that. So I’m not really familiar with those systems either.
Striegel: Martin, you wanted to add on…
Martin: Both, all of your points. There are situations where your makeup of source water is so hard that the idea of being able to replace when you don’t have good water to work with to reduce your hardness. The problem I’ve seen with RO units is that they got the water too clean and you take out too many of the minerals and instead it’s unbalanced on a very corrosive. So, yes there are situations where if you could reduce the hardness overall that would be great, but I would think that using it on a fountain, particularly in the sun where you have a lot of evaporation, you are going to need makeup water during the summer to be able to replace it. So using an RO unit on an as needed basis to correct incoming water compliments as a fill situation, yes.
I have experimented with the various softening systems. Normally I live in area where there’s extremely hard water and I have to use a salt replacement system in my house to keep the scale from building up on everything. This worked but I don’t like having all the salt in the water. It’s a very measurable increase in the conductivity level and the total dissolved solids that you see in the water and that’s directly attributable to the salt. So, I’ve checked out whether all those other systems will work. There’s one system that uses heavy magnets that you attach on your incoming water supply system. The idea is that it’s supposed to realign all the constituents in the water. I can still get, particularly at the evaporation levels in say your toilets, you’ll see a scale buildup right at the evaporation. The newest one I’ve looked at is something called Pelican Brands Systems that uses heavy electric current but I haven’t tried it yet, but I’m skeptical it’s going to work. It is going to evaporate.
Krueger: Now I guess I should say to that in my part of the country we’re lucky that we don’t have hard water, and I also start with the assumption that the municipal water supply will be adjusted even though I’ve tested the water here in Kansas City and found some of the things like the phosphate levels are beyond what they should be. If you call the water department they’ll say, “Of course not, that’s not true.” But I’ve tested it, but I’m going on the basic assumption that the water being supplied will be properly saturated not super saturated. These are the problems. These aren’t problems I encounter enough to really get into.
Unknown: I would suggest that when you do the UV lamp replacement you also always replace the ballast. That’s just a suggestion for you and then secondly, I would very much appreciate if you could elaborate on your very last sentence, ozone causing possible damage to the art work sculpture.
Krueger: Well this is something I left kind of vague and said it’s something you should look into because ozone is oxygen and oxygen is very reactive and can cause a lot of damage. The question and I’ve heard this too that people with asthma and different conditions will really sense it. But I don’t know of a way of measuring ozone in the air easily and I’ve seen the ozone meter used in a public health department fountain in the lobby and have never heard of anybody having an effect which makes me think that by the time the water is flowing out there the ozone is pretty depleted because ozone depletes really quickly easily. That’s kind of why I left it a little bit vague about what the effects are and the other thing I remember too in graduate school is learning about filters used un museums, you don’t want to use something that creates ozone but I’ve not really come up with a good answer as to whether that ozone is really in the air anymore by the time it reaches the duct work in the museum, so I kind of leave that as a cautionary something to be aware of but they do work and from what I’ve seen they work really well in keeping the water clean.
Striegel: Yes, Okay.
Unknown: Just one quick comment about the ozone problem, the only paper that I know that’s really researched that is a paper that researched the effect of ozone on Japanese prints and dyes and it significantly changed the fading rate. So using it in the environment may not be the best thing until we know more.
Striegel: One last comment.
Unknown: On the ozone, you can actually use quite a bit of ozone safely by using a contact tank and then taking the off gas from that and you run it through an off gas that will take any excess ozone and revert it back to oxygen really quickly, the off gas is really granular activated carbon. So ideally by the time the water gets out to this tank by the time the water gets to the fountain there’s no more ozone.
Krueger: Exactly, and that’s kind of my suspicion with the one system that I’ve seen working is that by the time the water is pumped everywhere, it’s already done its thing and the ozone is back to normal oxygen.
Striegel: Thank you Robert.
A Manageable Approach for the Maintenance of Fountain Water by Robert Krueger
No matter the size or design, the one common element in all fountains is water. This talk addresses the need for monitoring and maintenance of the water chemistry in fountains by starting with an explanation of the chemistry of water and how it affects materials, and continues by outlining a straight-forward maintenance routine. Usually the driving force in addressing a fountain is to solve an aesthetic problem or a conservation concern. The fountain’s water chemistry can have the most degrading effect on an associated artwork, or the basin and mechanical system. No matter the material composition of the fountain, its mechanical system, or the type of artwork, there are some basic approaches that should be undertaken for the optimum fountain performance in regards to appearance and preservation.
Often the curatorial and maintenance focus is limited to keeping the water clean and free of algae. Managers of fountains often believe the publically accessible body of water must be treated as a swimming pool. While keeping the water clean may be important, it is usually done strictly to meet an aesthetic goal, while ignoring or not understanding the potential damage that can be caused by a specific course of treatment, or lack of treatment.
While killing algae may seem straightforward, the effect of this treatment on the artwork, water basin, and mechanical systems is often overlooked. In 2007 a rusting stainless steel sculpture in a fountain was studied to discover the cause of the corrosion, which ended up being the additives meant to keep the fountain free of biological growth. The following year the Noguchi Fountain at the Nelson-Atkins Museum of Art was examined to resolve an issue of reoccurring algae growth on the basalt surface. A method of treatment was needed that would not harm the artwork or the stainless steel elements of the fountain. Knowing that standard pool chemistry was problematic, a literature study of water treatment methodology was undertaken.
Continued research on this topic has resulted in a general routine to maintain fountain water so it is clean, safe and chemically benign for the artwork and other surfaces in contact with the water. The suggested maintenance will require about 20 minutes per week to care for the water in a fountain. The maintenance routine also acts as preventative conservation for the artwork and the related fountain systems. Although some of the chemistry may seem complicated, the maintenance is not, and all materials needed are readily available. This approach takes into consideration issues such as stopping unwanted biological growth, averting unpleasant odors (from poor water quality or added chemistry), corrosion, and degradation of artwork or fountain mechanical, and staining of surfaces.
Robert Krueger is an object conservator and proprietor of Cascadia Art Conservation Center in Portland, Oregon. He has a Masters in Conservation from State University of New York at Buffalo, and is a Professional Associate of the American Institute for Conservation of Historic and Artistic Works (AIC). Robert works with municipal collectors, universities, museums, and private collectors. His approach to conservation includes traditional conservation treatments as well as the preservation of artworks through preventative approaches. Robert works regularly with commissioning agencies and artists in reviewing materials and methods to guarantee the best approaches for longevity and durability. Robert’s interest in defining a manageable care methodology for fountains was forged after studying the effects of chlorinated fountain water on a stainless steel sculpture in downtown Portland in 2007.